Display device

ABSTRACT

A display device includes first and second transparent substrates; a plurality of gate bus lines and data bus lines on the first transparent substrate to define a plurality of pixels; a plurality of color filter layers under the second transparent substrates; and a plurality of microlenses under one of the first and second transparent substrates at positions corresponding to the gate and data bus lines, wherein at least two microlenses among the plurality of microlenses are corresponded to each of the gate or data bus lines in a width direction of each of the gate or data bus lines, and wherein a border between the at least two microlenses is substantially aligned with a center of a corresponding one of the gate and data bus lines, and wherein at least one microlens overlapped with one data bus line does not overlap with the other data bus lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of co-pending U.S. patent applicationSer. No. 08/889,732 filed on Jul. 8, 1997, which claims the benefitunder 35 U.S.C. § 119(a) to Korean Patent Application No. P96-28526filed on Jul. 15, 1996, all of which are hereby expressly incorporatedby reference into the present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to a transmissive-type displaydevice (“transmissive display device”). More particularly, the presentinvention relates to a dot matrix type display device having a displaypanel and multiple picture elements (“pixels”) arranged in a matrix toform a liquid crystal display (“LCD”), wherein the display panel isprovided with an array of microlenses.

Description of the Related Art

In general, LCDs are comprised of upper and lower substrates facing eachother as shown in FIG. 1. The lower substrate includes a plurality ofpixel electrodes 13 formed on a transparent glass substrate 10. Data buslines 12 are formed parallel to each other in a horizontal direction,and gate bus lines 11 are formed parallel to each other in a verticaldirection. Between the data bus lines 12 and the gate bus lines 11, anarray of the pixel electrodes 13 are formed.

On the transparent substrate 10, switching elements such as thin filmtransistors 15 (“TFTs”) are disposed for the respective pixels at eachcrossing area where the gate bus lines 11 and the data bus lines 12cross each other. The pixel electrodes 13 are electrically connected tothe output electrodes (e.g., drains) of the TFTs 15.

On the other hand, the upper substrate includes a color filter layer 21formed on a transparent glass substrate 20 and common electrodes 22formed on the color filter layer 21. As shown in FIG. 2, the colorfilter layer 21 includes a red color filter 21R, a green color filter21G, and a blue color filter 21B successively formed on the substrate20. Among the different arrangements of color filters, the mosaic-arrayis employed in an audio video (AV) mode and the striped array is used inan office automation (OA) mode.

Once the upper and lower substrates are individually formed, it isnecessary to join them for injecting liquid crystal 24 therebetween. Theupper substrate and the lower substrate may be joined so that the colorfilter layer 21 faces the pixel electrodes 13 formed on the transparentglass substrate 10.

Additionally, a black matrix 14 is formed over the gate bus lines 11 andthe data bus lines 12 corresponding to the border of the each colorfilter 21R, 21G and 21B. The black matrix 14 shields light which mayhave leaked from the gaps formed between the bus lines and the pixelelectrodes 13, and improves the contrast of the LCD by making theborders of the color filters more clear.

Generally, the size of the black matrix 14 is larger than that of eachbus line because of the misalignment arising from joining the uppersubstrate with the lower substrate. The gate bus lines 11 and the databus lines 12 are approximately 15 μm-40 μm and 10 μm-25 μm wide,respectively. Therefore, the black matrix 14 is slightly wider than thebus lines.

In the conventional LCDs having the above described elements, a lightsource is located at the backside of the transparent glass substrate 20.The black matrix 14 is formed on the transparent glass substrate 10 tocover the gate bus lines 11 and data bus lines 12. The light from thelight source, as depicted with a straight line in FIG. 2, is transmittedthrough the transparent glass substrate 20, the color filters 21R, 21Gand 21B, the common electrodes 22 and the liquid crystal 24,sequentially. This light passes through the portion of transparent glasssubstrate 10 having the pixel electrodes 13 thereon. But, the lightimpinging on the gate and data bus lines 11 and 12 are blocked by theblack matrix 14. As a result, the aperture ratio of the LCD and thebrightness of the device is reduced.

The aperture ratio is expressed by “the effective area of all thepixels” divided by “the total display area”. The aperture ratio equalsthe ratio of the recoverable light to all incident light (recoverableand unrecoverable light). (The unrecoverable light is the light blockedby the untransmissive portion of the display panel, and does notcontribute to displaying.) As the size of the untransmissive portionincreases, the aperture ratio decreases. The reduced aperture ratioleads to reproduction of dark pictures and poor image quality.

The LCDs may include a storage capacitor for assisting the cellcapacitance of the LCDs. There are two types of storage capacitors. Oneis a storage-on-common type in which the storage capacitor is formedseparately. The other is a storage-on-gate type in which a portion ofgate line functions as a storage capacitor electrode. The former has asmaller effective area for forming the pixels than the latter.Therefore, the aperture ratio of such LCDs and the brightness of thedisplay device is reduced.

In order to refine pictures on the display, the brightness of thebacklight must be increased and the size of the untransmissive portionmust be minimized. To increase the brightness of the backlight, moreelectricity (power) is required; however, such is undesirable because itis costly.

Many different methods have been developed to improve the aperture ratioof the LCDs, e.g., enlarging the area of pixel electrodes or enlargingthe pixel size. To enlarge the pixel size, however, the other elementsof the LCD such as gate bus lines, source bus lines, TFTs and so on,need to be minimized. But, photo-lithography and etching has a limit onminimizing these elements. Further, the width of bus lines cannot bereduced below a certain level. Therefore, it is difficult to manufactureLCDs with an improved aperture ratio. But, even if the pixel size wereincreased by the above methods, the aperture ratio is generally 40% or50% at best.

To solve the problems described above, an LCD with a different structurehas been proposed in which the display panel with an array ofmicrolenses are formed on one side or both sides of the panel. Such astructure is disclosed in Japanese Laid-Open Patent Publications No.60-262131 and No. 61-11788. Referring to FIG. 3, one of the advantagesof such known display devices is that the light rays incident onto theportion of display panel which does not contribute to displaying, arefocused on the pixel electrodes using elements 31 and pass throughelements 32. As a result, the transmittance of the LCD having the sameaperture ratio is increased.

Another proposal for further enhancing the above mentioned device isdisclosed in U.S. Pat. No. 5,187,599. Referring to FIG. 4, such adisplay device comprises a first array of microlenses 31′ disposed onthe incident side of the display panel, and a second array ofmicrolenses 32′ disposed on the incident side of the other displaypanel, each microlens being disposed according to the respective pixels.The focal points of the first array of microlenses are identical withthose of the second array of microlenses, and the focal length of eachmicrolens in the first array is greater than that of the second array.Therefore, the light rays incident on the untransmissive portion of thedisplay panel is redirected by condensing the diverging rays.

The above suggested structure of the LCD are to increase thetransmittance of the light and to acquire the effect of having anincreased aperture ratio, without actually increasing the apertureratio. Each microlens covers the entire pixel electrode. The height ofthe microlenses need to be greater than 50 μm to cover the dimension ofeach pixel electrode having generally 100 μm×300 μm. However, inpractice, it is difficult to form the LCD having microlenses greaterthan 50 μm in height, resulting relatively flat lenses. Accordingly, thetransmittance of conventional LCDs cannot be effectively improved.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an LCD which has animproved transmittance.

Another object of the present invention is to provide a brighter LCDwith low power consumption.

Still another object of the present invention is to provide an LCD whichhas an improved contrast ratio.

Still another object of the present invention is to provide an LCD whichovercomes the disadvantages and problems encountered in the conventionalLCDs.

In order to achieve the above and other objects, an LCD according to thepresent includes multi-microlenses corresponding to the border of theuntransmissive portions of the LCD. More particularly, the LCD accordingto the embodied invention includes first and second transparentsubstrates facing each other, a plurality of gate and data bus linesformed on the first substrate, a plurality of color filters formed onthe second substrate, and a plurality of microlenses formedcorresponding to the gate and data bus lines. In case that storagecapacitor lines including storage capacitors are formed on the firstsubstrate for storage capacitance, it is desirable to have a pluralityof microlenses at the position corresponding to the storage capacitorlines in order to improve the transmittance.

These and other objects of the present application will become morereadily apparent from the detailed description given hereinafter.However, it should be understood that the detailed description andspecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention and wherein:

FIG. 1 is a three-dimensional view showing a structure of a conventionalLCD;

FIG. 2 is a partial, cross-sectional view showing a light path in theconventional LCD of FIG. 1;

FIG. 3 is a cross-sectional view showing a light path in a conventionalLCD;

FIG. 4 is a cross-sectional view showing a light path in anotherconventional LCD.

FIGS. 5A-5B, 6A-6B, and 7A-7B are cross-sectional views showing examplesof different configurations and shapes of microlenses for an LCDaccording to the embodiments of the present invention;

FIG. 8 is a cross-sectional view of an LCD according to a first exampleof a first embodiment of the present invention;

FIG. 9 is a cross-sectional view of an LCD according to a second exampleof the first embodiment of the present invention.

FIG. 10 is a cross-sectional view of an LCD according to a third exampleof the first embodiment of the present invention;

FIG. 11 is a cross-sectional view of an LCD according to a fourthexample of the first embodiment of the present invention;

FIG. 12 is a cross-sectional view of an LCD according to a first exampleof a second embodiment of the present invention.

FIG. 13 is a cross-sectional view of an LCD according to a secondexample of the second embodiment of the present invention;

FIG. 14 is a cross-sectional view of an LCD according to a third exampleof the second embodiment of the present invention;

FIG. 15 is a cross-sectional view of an LCD according to a first exampleof a third embodiment of the present invention;

FIG. 16 is a cross-sectional view of an LCD according to a secondexample of the third embodiment of the present invention; and

FIG. 17 is a cross-sectional view of an LCD according to an example of afourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The LCDs according to the preferred embodiments of the present inventionwill be described with reference to FIGS. 5 through 17. The LCDaccording to the first through fourth embodiments of the presentinvention includes a plurality of microlenses for effectivelyredirecting light from a light source all onto the pixel electrodes ofthe LCD, with simplicity. Generally, a path of light is depicted in theFigures by a line with arrow.

FIGS. 8-11 show cross-sectional views of examples of an LCD according tothe first embodiment of the present invention.

As shown in FIG. 8, the first example of the LCD according to the firstembodiment of the present invention includes a plurality of microlenses131 formed on a color filter layer 121 containing color filters 121R,121G and 121B. The color filter layer 121 is formed on a secondtransparent glass substrate 120. The microlenses 131 are covered with anovercoat material, such as acrylic resin to form an overcoat layer 132.Common electrodes 122 are formed on the overcoat layer 132 andconstitute a transparent conductive layer made of ITO. Pixel electrodes113 are formed on a first transparent glass substrate 110, and a blackmatrix 114 is formed to cover gaps between the pixel electrodes 113 anddata bus lines 112 and gaps between the pixel electrodes 113 and gatebus lines.

As shown in FIG. 9, the second example of the LCD according to the firstembodiment of the present invention includes a plurality of microlenses231 formed directly on a second glass substrate 220 and covered with anovercoat layer 232 made of acrylic resin. A color filter layer 221having red, blue, and green filters 221R, 221B, 221G is then formed onthe overcoat layer 232. On the color filter layer 221, common electrodes222 are formed. Other elements, such as the data bus lines 112, pixelelectrodes 113, black matrix 114 and gate bus lines are formed on thefirst substrate 110 in a manner similar to the LCD of FIG. 8.

As shown in FIG. 10, the third example of the LCD according to the firstembodiment of the present invention includes a plurality of microlenses331 formed on the outer surface of a second transparent glass substrate320. The microlenses 331 are covered with an overcoat layer 332 made ofacrylic resin. On the inner surface of the second substrate 320, a colorfilter layer 321 having red, blue, and green filters 321R, 321B, 321G isformed. Then on the color filter layer 321, common electrodes 322 areformed. Other elements, such as the data bus lines 112, pixel electrodes113, black matrix 114 and gate bus lines are formed on the firstsubstrate 110, in a manner similar to the LCDs of FIGS. 8 and 9.

As shown in FIG. 11, the fourth example of the LCD according to thefirst embodiment of the present invention includes a plurality ofmicrolenses 431 formed by selectively etching the outer surface portionof an overcoat layer 432 formed on a second transparent glass substrate420. The spaces formed by etching the overcoat layer 432 are filled witha material different from the material constituting the overcoat layer432 in refraction index. For example, the overcoat layer 432 may beformed of acrylic resin and the microlenses 431 may be formed of anorganic material, such as benzocyclobutene (“BCB”). Similarly theovercoat layer 432 may be formed of BCB and the microlenses 431 may beformed of acrylic resin.

On the inner surface of the second substrate 420, a color filter layer421 having red, blue and green filters 421R, 421B, 421G is formed. Thenon the color filter layer 421, common electrodes 422 are formed. Otherelements, such as the data bus lines 112, pixel electrodes 113, blackmatrix 114 and gate bus lines are formed on the first substrate 110, ina manner similar to the LCDs of FIGS. 8, 9 and 10.

The microlenses 131, 231, 331 and 431 are preferred to be about 6 μm inwidth and about 3 μm in height, in view of the distance between thecolor filter layer and data bus lines 112 (or gate bus lines), and inview of the width of each bus line and the refraction index of themicrolenses.

According to the first embodiment, the light from the backlight, whichis shielded by the bus lines in the conventional LCDs, is refracted whenarriving at the surface of each microlens 131, 231, 331 and 431, andpasses through the pixel electrodes 113 and first transparent glasssubstrate 110. As a result, almost all incident light can betransmitted, increasing the transmittance substantially.

In these cases, a micro black matrix whose width is narrower than thatof bus lines can be additionally disposed between the color filters onthe second transparent substrate, in order to further emphasize thecolor difference with clear boundaries.

Furthermore, according to the first embodiment of the present invention,the microlenses 131, 231, 331, and 431 are formed on the secondsubstrate corresponding to the edge portions of the pixel electrodes andto cover the bus lines and the gaps between the bus lines and pixelelectrodes. The middle portions of the pixel electrodes 113 may not becovered by the microlenses.

FIGS. 12-14 show cross-sectional views of examples of an LCD accordingto the second embodiment of the present invention. In the secondembodiment, microlenses are disposed on the lower substrate and thebacklight is disposed behind the lower substrate.

As shown in FIG. 12, the first example of the LCD according to thesecond embodiment of the present invention includes a plurality ofmicrolenses 155 formed on the inner surface of a first transparent glasssubstrate 150. The microlenses 155 are covered with an overcoat layer156 made of acrylic resin. On the overcoat layer 156, other elements,such as the data bus lines 152, pixel electrodes 153, a black matrix 154and gate bus lines are formed.

In the upper substrate, a color filter layer 121′ having red, blue andgreen filters 121R′, 121B′ and 121G′ is formed on a second transparentglass substrate 120′. On the color filter layer 121′, common electrodes122′ are formed.

Further, the backlight is disposed behind the first transparentsubstrate 150 and directs the light toward the second transparentsubstrate 120′. The incident light is focused by the microlenses 155 sothat it is directed to the pixel electrodes 153 and not to the data andgate bus lines. As a result, the microlenses 155 redirect light whichwould have been blocked and scattered by the bus lines onto the edgeportions of the pixel electrodes 153. Accordingly, the transmittance isincreased and the LCD with an increased brightness and increased powerefficiency is produced.

As shown in FIG. 13, the second example of the LCD according to thesecond embodiment of the present invention includes a plurality ofmicrolenses 165 formed on the outer surface of a first transparent glasssubstrate 160. These microlenses 165 are covered with an overcoat layer166 made of benzocyclobutene or acrylic resin. On the inner surface ofthe first transparent substrate 160, other elements, such as data buslines 162, pixel electrodes 163, a black matrix 164 and gate bus linesare formed.

In the upper substrate, common electrodes 122′, a color filter layer121′ having color filters 121R′, 121B′, 121G′, and a second transparentglass substrate 120′ are formed in a manner similar to the uppersubstrate of the LCD in FIG. 12.

As shown in FIG. 14, the third example of the LCD according to thesecond embodiment of the present invention includes a plurality ofmicrolenses 175 formed by selectively etching the outer surface portionof an overcoat layer 176 formed on a first transparent glass substrate170. The spaces formed by etching the overcoat layer 176 may be filledwith a material such as acrylic resin or BCB. For example, if theovercoat layer 176 is made of acrylic resin, the spaces may be filledwith BCB. If the overcoat layer 176 is made of BCB, the spaces may befilled with acrylic resin. On the inner surface of the first transparentsubstrate 170, other elements, such as data bus lines 172, pixelelectrodes 173, a black matrix 174 and gate bus lines are formed.

In the upper substrate, common electrodes 122′, a color filter layer121′ having color filters 121R′, 121B′, 121G′, and a second transparentglass substrate 120′ are formed in a manner similar to the LCDs of FIGS.12 and 13.

According to the second embodiment of the present invention, the lightsource is positioned at the backside of the first transparent glasssubstrate 150, 160 and 170. When the light from the light source hitsthe surface of the microlenses 155, 165 and 175, it is refracted. Thatis, the light which is blocked by the gate and data bus lines in theconventional LCDs is refracted as it passes through the microlenses. Therefracted light then passes through the pixel electrodes 153, 163 and173 and the second transparent substrate 120′. As a result, almost allincident light can be transmitted and the transmittance is consequentlyincreased.

In these cases, a micro black matrix whose width is less than that ofthe bus lines can be additionally disposed between the color filters onthe second transparent substrate, to emphasize the different colors.

FIGS. 15 and 16 show cross-sectional views of examples of an LCDaccording to the third embodiment of the present invention.

As shown in FIG. 15, the first example of the LCD according to the thirdembodiment of the present invention includes a plurality of microlenses531 formed by selectively etching the outer surface portion of a secondtransparent glass substrate 520. The spaces formed by etching the secondsubstrate 520 may be filled with a material 532, such as acrylic resin.

On the inner surface of the second transparent substrate 520, a colorfilter layer 521 having red, blue and green filters 521R, 521B and 521Gis formed. Between these color filters, a black matrix 514 having awidth larger than the width of each bus line is formed, in accordancewith the joining margin of the second transparent substrate 520 and afirst transparent glass substrates 510. On the color filter layer 521,common electrodes 522 are formed.

In the lower substrate, data bus lines 512, pixel electrodes 513, andgate bus lines are formed on the first transparent glass substrate 510.

Here, a backlight is located behind the second substrate 520. The lightwhich would have been blocked by the black matrix 514 is redirected ontothe color filter layer 521 and passes through the pixel electrodes 513.

As shown in FIG. 16, the second example of the LCD according to thethird embodiment of the present invention includes a plurality ofmicrolenses 631 formed in the lower substrate. By selectively etchingthe outer surface portion of the first transparent glass substrate 610,the microlenses 631 are shaped. The spaces formed by etching the firstsubstrate 610 may be filled with a material 632, such as an acrylicresin.

On the inner surface of the first transparent substrate 610, data buslines 612, pixel electrodes 613, and gate bus lines are formed. In theupper substrate, a color filter layer 621 having red, blue and greenfilters 621R, 621B and 621G is formed on a second transparent glasssubstrate 620. Between these color filters, a black matrix 614 having awidth larger than the width of each bus line is formed, in accordancewith the joining margin of the first and second transparent substrates610 and 620. On the color filter layer 621, common electrodes 622 areformed.

Here, the backlight is located behind the first substrate 610. The lightwhich would have been blocked by the black matrix 614 is redirected ontothe color filter layer 621 and passes through the pixel electrodes 613.

Therefore, according to the third embodiment of the present invention,the transmittance and aperture ratio of the LCD is increased withincreased power efficiency.

FIG. 17 shows a cross-sectional view of an LCD according to the fourthembodiment of the present invention.

The LCDs according to the first and second embodiments comprise a BM(black matrix) formed on arrays of TFTs formed on a first substrate. Thetransmittance can be increased by enlarging the size of pixelelectrodes, avoiding the BM-on-array structure. The LCD according to thefourth embodiment of the present invention is formed with enlarged pixelelectrodes, which includes pixel electrodes formed on a passivationlayer made of benzocyclobutene.

The LCD according to the fourth embodiment further includes microlensesformed at each pixel border area of the color filter layer correspondingto the gate bus lines and the data bus lines. The microlenses 731 arecovered with an overcoat layer 732 made of an organic film such as BCBor acrylic resin. The overcoat layer is formed to enhance stability inrubbing and to improve leveling. The overcoat layer may not be necessaryif stability in rubbing and improvement in leveling are alreadyobtained.

This embodiment provides pixel electrodes 713 larger than those of anLCD comprising a typical BM-on-array structure.

As shown in FIG. 17, the LCD includes a plurality of microlenses 731formed on the inner surface of a color filter layer 721. The colorfilter layer having red, green and blue filters 721R, 721G and 721B isformed on the inner surface of a second transparent glass substrate 720.On the microlenses 731, an overcoat layer 732 made of benzocyclobuteneis formed, and common electrodes 722 are formed thereon.

In the lower substrate, a passivation layer 715 made of an organicmaterial, such as benzocyclobutene is formed between data bus lines 712and pixel electrodes 713, so that larger pixel electrodes can be formed.A black matrix is formed only on the gate bus lines formed on a firsttransparent glass substrate 710.

In the fourth embodiment of the present invention, a light from thebacklight travels straight through the second substrate 720 and isrefracted at the surface of the microlenses 731. The refracted lightimpinges on the pixel electrodes 713, but not on the gate and data buslines. Consequently, most of the light from the light source istransmitted through the first transparent glass substrate 710.

According to the first through fourth embodiments of the presentinvention, when the microlenses (131, 155, 165, 175, 231, 331, 431, 531,631 and 731) are formed at the positions corresponding to the gate andsource bus lines, almost no incident light is lost. Consequently, theaperture ratio is improved up to 90%, compared to at most 70% in theconventional LCDs. Therefore, an LCD which is driven by a low power andhas a high transmittance is obtained.

With respect to forming the microlenses, a discussion on how large thescale of microlenses is and where the microlenses are formed is providedbelow.

In order to design the microlenses for condensing or dispersing theincident light, the relationship between the incident angle and therefracted angle of the light is considered. The refraction angle of thelight is calculated from the following equation (1) known as the Snell'slaw, which shows the relationship between refraction indices andrefraction angles.

n ₂ /n ₁=sin θ₁/sin θ₂   (1)

According to the equation (1), the refraction angle θ₂ of incident lightat an angle θ₁ to the normal line of each microlens is determined by therefraction index of the material (n₁) of the microlens and therefraction index of the material (n₂) being in contact with themicrolens.

In the present invention, considering the effects of the microlenses andeasiness of making them, microlenses having the width of 4 μm-30 μm andthe height of greater than 0.5 μm are suggested.

The microlenses according to the embodiments of the present inventionare formed at the positions according to the gate bus lines and the databus lines so as to obtain the best effect. In a case where the lightsource is positioned at the backside of the second substrate having acolor filter layer, it is desirable to form the microlenses on the outeror inner side of the second substrate. In a case where the light sourceis positioned at the backside of the first substrate having pixelelectrodes, it is desirable to form the microlenses on the outer orinner side of the first substrate. However, the position of themicrolenses is not restricted to the above. That is, as long as themicrolenses function to focus and redirect the light which travels tothe gate bus lines and the data bus lines, the shape of microlenses canbe varied.

FIGS. 5A-7B are cross-sectional and plan views showing examples ofdifferent configurations and shapes of microlenses for the LCDsaccording to the present invention. These examples are applicable to thefirst through fourth embodiments of the present invention. Each of themicrolenses of the present invention can be formed to be equal to orgreater (e.g., more than 30 μm) than each line width at the positionscorresponding to the gate data lines and data bus lines.

As shown in FIGS. 5A and 5B, the microlens (141) cover each data busline 142 and each gate bus line 144. The microlenses 141 are positionedso that the border therebetween is substantially aligned with the centerof each bus line (shown by the dotted line). Also, a width of the gatebus line 144 or the data bus line 142 extends substantially betweencenters of the micro lenses (141). Two microlenses (141) are disposedover the gate bus lines (144) in a width direction of each gate bus line(144), and two microlenses (141) are disposed over the data bus lines(142) in a width direction of each data bus line (142). The twomicrolenses 141 are positioned so that the border therebetween issubstantially aligned with the center of each bus line (shown by thedotted line). As further shown by FIG. 5B, at least three microlensesare disposed over each of the gate and data bus lines corresponding toone pixel in a length direction. In FIGS. 6A and 6B, moreover, themicrolenses (145) can also be formed at any position in the LCD panel,including where the pixel electrodes 143 are.

As shown in FIGS. 7A and 7B, the microlens (146) having the same size asthe color filter layer can be formed at a position corresponding to eachcolor filter layer, covering the corresponding array of pixel electrodes143. The microlens 146 includes edge portions which are curved and whichcover the area in which the color filter layer overlaps the gate buslines 141 and data bus lines 142. These edge portions correspond to alight shielding area (non-transmissive portion), such as gate and databus lines, a black matrix, and storage capacitor lines. The shape of theedge portions allows the incident light to be focused onto thetransmissive portion. The microlens 146 further includes a substantiallyflat portion for allowing the light to pass straight through the pixelelectrodes 143.

The microlenses according to the first through fourth embodiments of thepresent invention can be made of a different material or can be formedby patterning LCD elements such as a color filters, pixel electrodes,insulating layers, a transparent glass substrate, etc. into the shape ofa lens. As described above, an overcoat layer is formed on themicrolenses for increased stability in rubbing and upgrading theuniformity of the substrate surface.

According to the present invention, although the amount of an incidentlight is not increased, the amount of the transmitted light isincreased. In other words, though the aperture ratio, namely the size oftransmissive portion, is not increased, the same effect of having anincreased aperture ratio is achieved.

The effect of the present invention is increased when it is applied tothe LCD structures, in which the pixel electrodes overlap the data buslines and an organic insulator such as BCB is inserted between the pixelelectrodes and the bus lines, for increasing the size of the pixels. Theeffect is also increased by forming a black matrix (BM-on-array) on thefirst transparent glass substrate.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A display device comprising: first and secondtransparent substrates; a plurality of gate bus lines and data bus lineson the first transparent substrate to define a plurality of pixels; aplurality of color filter layers under the second transparentsubstrates; and a plurality of microlenses under one of the first andsecond transparent substrates at positions corresponding to the gate anddata bus lines, wherein at least two microlenses among the plurality ofmicrolenses are corresponded to each of the gate or data bus lines in awidth direction of each of the gate or data bus lines, and wherein aborder between the at least two microlenses is substantially alignedwith a center of a corresponding one of the gate and data bus lines, andwherein at least one microlens overlapped with one data bus line doesnot overlap with the other data bus lines.
 2. The display deviceaccording to claim 1, further comprising: a black matrix over an innersurface of the first transparent substrate.
 3. The display deviceaccording to claim 1, further comprising: a light source located behindthe one of the first and second transparent substrates on which themicrolenses are formed.
 4. The display device according to claim 1,further comprising an overcoat layer covering the plurality ofmicrolenses.
 5. The display device according to claim 4, wherein theplurality of color filter layers are positioned under the overcoatlayer.
 6. The display device according to claim 1, wherein the pluralityof color filter layers are positioned between the second transparentsubstrate and the plurality of microlenses.
 7. The display deviceaccording to claim 1, wherein each of the microlenses includes a curvedend portion and a substantially flat body portion.
 8. The display deviceaccording to claim 1, further comprising an overcoat layer under thefirst transparent substrate, wherein the plurality of microlenses formedby selectively etching a bottom surface of the overcoat layer andfilling a different material from the overcoat layer.
 9. The displaydevice according to claim 8, wherein each of microlenses is a concavelens.
 10. The display device according to claim 1, wherein the pluralityof microlenses are formed by selectively etching a bottom surface of thefirst transparent substrate and filling with a different material fromthe first transparent substrate.
 11. The display device according toclaim 10, wherein each of microlenses is a concave lens.
 12. A displaydevice comprising: a transparent substrate; a plurality of pixels on thetransparent substrate, the a plurality of pixels having a plurality ofgate bus lines and data bus lines; and a plurality of microlenses underthe transparent substrate, wherein at least two microlenses among theplurality of microlenses correspond to each of the gate or data buslines in a width direction of each of the gate or data bus lines, andwherein at least two microlenses correspond to one pixel.
 13. Thedisplay device according to claim 12, further comprising an overcoatlayer covering the plurality of microlenses.
 14. The display deviceaccording to claim 13, further comprising a plurality of color filterlayers under the overcoat layer.
 15. The display device according toclaim 12, wherein each of the microlenses includes a curved end portionand a substantially flat body portion.
 16. The display device accordingto claim 12, further comprising an overcoat layer under the transparentsubstrate, wherein the plurality of microlenses formed by selectivelyetching a bottom surface of the overcoat layer and filling a differentmaterial from the overcoat layer.
 17. The display device according toclaim 16, wherein each of microlenses is a concave lens.
 18. The displaydevice according to claim 12, wherein the plurality of microlenses areformed by selectively etching a bottom surface of the transparentsubstrate and filling with a different material from the transparentsubstrate.
 19. The display device according to claim 18, wherein each ofmicrolenses is a concave lens.
 20. A display device comprising: firstand second substrates; a plurality of pixels on the first substrate, thea plurality of pixels having a plurality of gate bus lines and data buslines; a plurality of color filter layers corresponding to the pluralityof pixels; and a plurality of microlenses under one of the first andsecond substrates, wherein at least two microlenses correspond to eachof the gate or data bus lines in a width direction of each of the gateor data bus lines, and at least three microlenses are disposed over eachof the gate or data bus lines corresponding to one pixel in a lengthdirection of each of the gate or data bus lines, and wherein at leastone microlens overlapped with one data bus line does not overlap withthe other data bus lines.